class Point{
    int x,y;
    void setXY(int m,int n){
       x=m;
       y=n;
   }
}
public class Example4_4{
   public static void main(String args[]){
     Point p1,p2;
     p1=new Point();
     p2=new Point();
     System.out.println("p1的引用:"+p1);
     System.out.println("p2的引用:"+p2);
     p1.setXY(1111,2222);
     p2.setXY(-100,-200);
     System.out.println("p1的x,y坐标:"+p1.x+","+p1.y);
     System.out.println("p2的x,y坐标:"+p2.x+","+p2.y);
     p1=p2;
     System.out.println("将p2的引用赋给p1后：");
     System.out.println("p1的引用:"+p1);
     System.out.println("p2的引用:"+p2);
     System.out.println("p1的x,y坐标:"+p1.x+","+p1.y);
     System.out.println("p2x,y的坐标:"+p2.x+","+p2.y);
   }
  }
